Sanitary hydrants prevent harmful bacteria, such as Escherichia coli (E. coli), that may be in the groundwater or surrounding soil from contaminating the water source and/or water exiting the hydrant. Many states and local municipalities have adopted hydrant requirements to prevent such contamination, an example of which may be found in Rule 1057 of the American Society of Sanitary Engineers (ASSE). These requirements have forced municipalities, ranchers, camp sites, and other entities with outdoor operations to use contamination-proof “sanitary” hydrants as opposed to the “non-sanitary” hydrants previously employed to accommodate water delivery needs.
To prevent freeze-related damage, non-sanitary hydrants known in the art employ weep holes positioned below the frost line to drain water contained within the hydrant after the hydrant is shut off. Weep holes, however, do not always prevent freezing. Due to fluctuations in the degree of water saturation of the ground surrounding the hydrant (which may be caused at least in part due to frequent use of the hydrant), the drain water may not always percolate into the ground before it freezes. In addition, if the groundwater level rises above the weep hole, then groundwater may enter the hydrant through the weep hole. The groundwater may be contaminated. If so, each time the hydrant is turned on, the contaminated water in the operating pipe may mix with the water drawn from the water source, thereby causing spoiled water to be expelled by the hydrant and/or spoilage of the water source.
To prevent the backflow of water into the non-sanitary hydrant, a check valve is often employed. If, however, the check valve wears out or malfunctions, contaminated water may enter the hydrant, thus endangering crops, livestock, and humans.
One skilled in the art will appreciate that hydrants employing weep holes open to groundwater may be susceptible to deliberate contamination by a malfeasor, or even to accidental contamination by a careless actor. More specifically, it is easily seen how contaminants placed into the ground could infiltrate into a damaged hydrant and spoil a water supply. In addition, an ancillary problem with non-sanitary hydrants is that contaminated water may affect the food supply. For example, in 2006 an E. coli scare occurred in the United States, wherein people became sick or died after they consumed spinach that had been watered and/or cleaned by water from a source that had been polluted by E. coli. Hydrants that are isolated from the surrounding soil are thus more desirable than those that are open to the surrounding soil, at least because they substantially prevent water spoilage by natural and unnatural sources.
One way to address this concern is to provide a freezeless sanitary hydrant that does not include a path for water to exit (and therefore does not include a path for contaminated water to enter) the hydrant after shut-off. For example, U.S. Pat. No. 5,246,028 to Vandepas (“Vandepas”), which is incorporated by reference in its entirety herein, discloses a sanitary hydrant that includes an isolated reservoir that contains water below the frost line after the hydrant is shut off. When the hydrant is turned on, water from the reservoir is fed into the operating pipe along with the water from the source. Thus the water that previously drained from the operating pipe (e.g. the portion of the hydrant between the reservoir and the hydrant head) never has a chance to become contaminated. Vandepas employs a venturi that reduces the pressure of the water entering the hydrant, which suctions the stored water from the reservoir to be mixed with the inlet water. Venturi-dependent systems, however, require several parts (which add to the cost of such systems) and are often undesirable because they are difficult to fabricate, install and repair.